The present invention generally relates to low compressive stress doped silicate glass films for STI applications. By way of non-limited example, the stress-lowering dopant may be a fluorine dopant, a germanium dopant, or a phosphorous dopant. The low compressive stress STI films will generally exhibit a compressive stress of less than 180 MPa, and preferably less than about 170 MPa. In certain embodiment, the STI films of the invention will exhibit a compressive stress less than about 100 MPa. Further, in certain embodiments, the low compressive stress STI films of the invention will comprise between about 0.1 and 25 atomic % of the stress-lowering dopant.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of depositing a low compressive stress, shallow trench isolation (STI) film with good gap fill characteristics on a substrate, said method comprising: (a) positioning a substrate in a deposition chamber, wherein said substrate comprises at least one isolation trench between adjacent raised surfaces formed by anisotropic etching; (b) providing a gas mixture to the deposition chamber in one or more steps, wherein the gas mixture comprises a silicon source gas, a stress-lowering dopant source gas, at least one fluent source gas, and an oxidizer; (c) reacting the gas mixture in the presence of an electric field to generate a plasma having an ion density of at least 10 11 ions/cm 3 ; (d) and exposing said substrate to said plasma at a temperature greater than about 450° C. under conditions sufficient to thereby deposit a low compressive stress STI film within said isolation trench; wherein said STI film exhibits a compressive stress of less than about 170 MPa.
2. The method of claim 1 , wherein said substrate farther comprises a pad oxide and a pad nitride at predetermined locations thereon, and said at least one isolation trench comprises a liner oxide formed on the wall thereof to thereby improve gap-fill and adhesion properties of said deposited STI film.
3. The method of claim 1 , wherein the silicon source gas is silane (SiH4).
4. The method of claim 1 , wherein the stress-lowering dopant source gas is selected from the group consisting of: a fluorine containing source gas, a germanium containing source gas, and a phosphorous containing source gas.
5. The method of claim 4 , wherein the fluorine containing source gas is selected from the group consisting of: carbon tetrafluoride (CF 4 ), fluoroethane (C 2 F 6 ), trifluoromethane (CHF 3 ), difluoromethane (CH 2 F 2 ), silicon tetrafluoride (SiF 4 ), nitrogen trifluoride (NF 3 ), and combinations thereof.
6. The method of claim 4 , wherein the germanium containing source gas is selected from the group consisting of: germanium tetrahydride (GeH 4 ) and germanium halides.
7. The method of claim 4 , wherein the phosphorous containing source gas is phosphine (PH 3 ).
8. The method of claim 1 , wherein said at least one fluent source gas comprises a hydrogen-source gas.
9. The method of claim 1 , wherein said at least one fluent source gas is selected from the group consisting of hydrogen (H 2 ), helium (He), argon (Ar), neon (Ne), and combinations thereof.
10. The method of claim 1 , wherein the at least one fluent source gas is provided to the deposition chamber at a flow rate in a range of about 0 sccm to about 1000 sccm.
11. The method of claim 1 , wherein the stress-lowering dopant source gas is a fluorine-containing source gas.
12. The method of claim 11 , wherein the fluorine-containing source gas: silicon source gas ratio in the gas mixture is in a range of about 1.0:4.0 to about 3.0:2.0.
13. The method of claim 11 , wherein (fluorine-containing source gas)/ (silicon containing source gas+fluorine containing source gas) in the gas mixture ranges from about 0.29 to about 0.60.
14. The method of claim 11 , wherein the STI film exhibits a compressive stress less than about 100 MPa.
15. The method of claim 11 , wherein the STI film exhibits a compressive stress less than about 90 MPa.
16. The method of claim 1 , wherein the stress-lowering dopant source gas is a germanium-containing source gas.
17. The method of claim 16 , wherein the germanium-containing source gas : silicon source gas ratio in the gas mixture is in a range of about 1.0:1.0 to about 1.0:4.0.
18. The method of claim 16 , wherein (germanium-containing source gas)/ (silicon containing source gas+germanium containing source gas) in the gas mixture ranges from about 0.25 to about 0.50.
19. The method of claim 16 , wherein the STI film exhibits a compressive stress less than about 100 MPa.
20. The method of claim 1 , wherein the stress-lowering dopant source gas is a phosphorous-containing source gas.
21. The method of claim 20 , wherein the phosphorous-containing source gas: silicon source gas ratio in the gas mixture is in a range of about 1.0:2.0 and 1.0:5.0.
22. The method of claim 20 , wherein (phosphorous-containing source gas)/ (silicon containing source gas+phosphorous containing source gas) in the gas mixture ranges from about 0.26 to about 0.48.
23. The method of claim 20 , wherein the STI film exhibits a compressive stress less than about 100 MPa.
24. The method of claim 1 , wherein the silicon source gas is provided to the deposition chamber at a flow rate in a range of about 10 sccm to about 200 sccm.
25. The method of claim 1 , wherein the stress-lowering dopant source gas is provided to the deposition chamber at a flow rate in a range of about 3 sccm to about 300 sccm.
26. The method of claim 1 , wherein the oxidizer is provided to the deposition chamber at a flow rate in a range of about 30 sccm to about 900 sccm.
27. The method of claim 1 , wherein the electric field is generated from one or more radio frequency (RF) powers within a range of about 1000 W to about 9 kW for a 300 mm wafer.
28. The method of claim 1 , wherein the STI film exhibits a compressive stress less than about 100 MPa.
29. The method of claim 1 , wherein said low compressive stress STI film comprises between about 0.1 and 25 at. % of said stress-lowering dopant.
30. A method of lowering the compressing stress of a shallow trench isolation (STI) film, said method comprising: (a) providing a gas mixture comprising a silicon source gas, a stress-lowering dopant source gas, at least one fluent source gas, and an oxidizer to a high density plasma chemical vapor deposition (HDP-CVD) chamber for deposition of a low compressive stress STI film on a substrate comprising at least one isolation trench via high density plasma chemical vapor deposition (HDP-CVD); and (b) generating a plasma within said HDP-CVD chamber to thereby deposit said low compressive stress STI film within said at least one isolation trench on said substrate; wherein said substrate is heated to a temperature greater than 450° C. during said deposition; wherein said gas mixture comprises sufficient stress-lowering dopant source and said STI film is deposited under conditions sufficient to result in the deposit of a STI film that exhibits a compressive stress of less than about 170 MPa.
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October 17, 2005
July 17, 2007
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